EditorWindow:
class EditorWindow : public Fl_Double_Window { public: EditorWindow(int w, int h, const char* t); ~EditorWindow(); Fl_Window *replace_dlg; Fl_Input *replace_find; Fl_Input *replace_with; Fl_Button *replace_all; Fl_Return_Button *replace_next; Fl_Button *replace_cancel; Fl_Text_Editor *editor; char search[256]; };
int changed = 0; char filename[256] = ""; Fl_Text_Buffer *textbuf;
The textbuf
variable is the text editor buffer for our window class described previously. We'll cover the other variables as we build the application.
Fl_Menu_Item menuitems[] = { { "&File", 0, 0, 0, FL_SUBMENU }, { "&New File", 0, (Fl_Callback *)new_cb }, { "&Open File...", FL_CTRL + 'o', (Fl_Callback *)open_cb }, { "&Insert File...", FL_CTRL + 'i', (Fl_Callback *)insert_cb, 0, FL_MENU_DIVIDER }, { "&Save File", FL_CTRL + 's', (Fl_Callback *)save_cb }, { "Save File &As...", FL_CTRL + FL_SHIFT + 's', (Fl_Callback *)saveas_cb, 0, FL_MENU_DIVIDER }, { "New &View", FL_ALT + 'v', (Fl_Callback *)view_cb, 0 }, { "&Close View", FL_CTRL + 'w', (Fl_Callback *)close_cb, 0, FL_MENU_DIVIDER }, { "E&xit", FL_CTRL + 'q', (Fl_Callback *)quit_cb, 0 }, { 0 }, { "&Edit", 0, 0, 0, FL_SUBMENU }, { "&Undo", FL_CTRL + 'z', (Fl_Callback *)undo_cb, 0, FL_MENU_DIVIDER }, { "Cu&t", FL_CTRL + 'x', (Fl_Callback *)cut_cb }, { "&Copy", FL_CTRL + 'c', (Fl_Callback *)copy_cb }, { "&Paste", FL_CTRL + 'v', (Fl_Callback *)paste_cb }, { "&Delete", 0, (Fl_Callback *)delete_cb }, { 0 }, { "&Search", 0, 0, 0, FL_SUBMENU }, { "&Find...", FL_CTRL + 'f', (Fl_Callback *)find_cb }, { "F&ind Again", FL_CTRL + 'g', find2_cb }, { "&Replace...", FL_CTRL + 'r', replace_cb }, { "Re&place Again", FL_CTRL + 't', replace2_cb }, { 0 }, { 0 } };
Once we have the menus defined we can create the Fl_Menu_Bar widget and assign the menus to it with:
Fl_Menu_Bar *m = new Fl_Menu_Bar(0, 0, 640, 30); m->copy(menuitems);
We'll define the callback functions later.
w->editor = new Fl_Text_Editor(0, 30, 640, 370); w->editor->buffer(textbuf);
So that we can keep track of changes to the file, we also want to add a "modify" callback:
textbuf->add_modify_callback(changed_cb, w); textbuf->call_modify_callbacks();
Finally, we want to use a mono-spaced font like FL_COURIER:
w->editor->textfont(FL_COURIER);
Figure 4-1: The search and replace dialog
Fl_Window *replace_dlg = new Fl_Window(300, 105, "Replace"); Fl_Input *replace_find = new Fl_Input(70, 10, 200, 25, "Find:"); Fl_Input *replace_with = new Fl_Input(70, 40, 200, 25, "Replace:"); Fl_Button *replace_all = new Fl_Button(10, 70, 90, 25, "Replace All"); Fl_Button *replace_next = new Fl_Button(105, 70, 120, 25, "Replace Next"); Fl_Button *replace_cancel = new Fl_Button(230, 70, 60, 25, "Cancel");
editor
widget:
void changed_cb(int, int nInserted, int nDeleted,int, const char*, void* v) { if ((nInserted || nDeleted) && !loading) changed = 1; EditorWindow *w = (EditorWindow *)v; set_title(w); if (loading) w->editor->show_insert_position(); }
The set_title()
function is one that we will write to set the changed status on the current file. We're doing it this way because we want to show the changed status in the window's title bar.
void copy_cb(Fl_Widget*, void* v) { EditorWindow* e = (EditorWindow*)v; Fl_Text_Editor::kf_copy(0, e->editor); }
void cut_cb(Fl_Widget*, void* v) { EditorWindow* e = (EditorWindow*)v; Fl_Text_Editor::kf_cut(0, e->editor); }
void delete_cb(Fl_Widget*, void* v) { textbuf->remove_selection(); }
find2_cb()
function to find the string:
void find_cb(Fl_Widget* w, void* v) { EditorWindow* e = (EditorWindow*)v; const char *val; val = fl_input("Search String:", e->search); if (val != NULL) { // User entered a string - go find it! strcpy(e->search, val); find2_cb(w, v); }
void find2_cb(Fl_Widget* w, void* v) { EditorWindow* e = (EditorWindow*)v; if (e->search[0] == '\0') { // Search string is blank; get a new one... find_cb(w, v); return; } int pos = e->editor->insert_position(); int found = textbuf->search_forward(pos, e->search, &pos); if (found) { // Found a match; select and update the position... textbuf->select(pos, pos+strlen(e->search)); e->editor->insert_position(pos+strlen(e->search)); e->editor->show_insert_position(); } else fl_alert("No occurrences of \'%s\' found!", e->search); }
If the search string cannot be found we use the fl_alert() convenience function to display a message to that effect.
check_save()
function to give the user the opportunity to save the current file first as needed:
void new_cb(Fl_Widget*, void*) { if (!check_save()) return; filename[0] = '\0'; textbuf->select(0, textbuf->length()); textbuf->remove_selection(); changed = 0; textbuf->call_modify_callbacks(); }
check_save()
function to give the user the opportunity to save the current file first as needed:
void open_cb(Fl_Widget*, void*) { if (!check_save()) return; char *newfile = fl_file_chooser("Open File?", "*", filename); if (newfile != NULL) load_file(newfile, -1); }
We call the load_file()
function to actually load the file.
void paste_cb(Fl_Widget*, void* v) { EditorWindow* e = (EditorWindow*)v; Fl_Text_Editor::kf_paste(0, e->editor); }
void quit_cb(Fl_Widget*, void*) { if (changed && !check_save()) return; exit(0); }
void replace_cb(Fl_Widget*, void* v) { EditorWindow* e = (EditorWindow*)v; e->replace_dlg->show(); }
void replace2_cb(Fl_Widget*, void* v) { EditorWindow* e = (EditorWindow*)v; const char *find = e->replace_find->value(); const char *replace = e->replace_with->value(); if (find[0] == '\0') { // Search string is blank; get a new one... e->replace_dlg->show(); return; } e->replace_dlg->hide(); int pos = e->editor->insert_position(); int found = textbuf->search_forward(pos, find, &pos); if (found) { // Found a match; update the position and replace text... textbuf->select(pos, pos+strlen(find)); textbuf->remove_selection(); textbuf->insert(pos, replace); textbuf->select(pos, pos+strlen(replace)); e->editor->insert_position(pos+strlen(replace)); e->editor->show_insert_position(); } else fl_alert("No occurrences of \'%s\' found!", find); }
void replall_cb(Fl_Widget*, void* v) { EditorWindow* e = (EditorWindow*)v; const char *find = e->replace_find->value(); const char *replace = e->replace_with->value(); find = e->replace_find->value(); if (find[0] == '\0') { // Search string is blank; get a new one... e->replace_dlg->show(); return; } e->replace_dlg->hide(); e->editor->insert_position(0); int times = 0; // Loop through the whole string for (int found = 1; found;) { int pos = e->editor->insert_position(); found = textbuf->search_forward(pos, find, &pos); if (found) { // Found a match; update the position and replace text... textbuf->select(pos, pos+strlen(find)); textbuf->remove_selection(); textbuf->insert(pos, replace); e->editor->insert_position(pos+strlen(replace)); e->editor->show_insert_position(); times++; } } if (times) fl_message("Replaced %d occurrences.", times); else fl_alert("No occurrences of \'%s\' found!", find); }
void replcan_cb(Fl_Widget*, void* v) { EditorWindow* e = (EditorWindow*)v; e->replace_dlg->hide(); }
void save_cb(void) { if (filename[0] == '\0') { // No filename - get one! saveas_cb(); return; } else save_file(filename); }
The save_file()
function saves the current file to the specified filename.
void saveas_cb(void) { char *newfile; newfile = fl_file_chooser("Save File As?", "*", filename); if (newfile != NULL) save_file(newfile); }
The save_file()
function saves the current file to the specified filename.
int check_save(void) { if (!changed) return 1; int r = fl_choice("The current file has not been saved.\n" "Would you like to save it now?", "Cancel", "Save", "Discard"); if (r == 1) { save_cb(); // Save the file... return !changed; } return (r == 2) ? 1 : 0; }
textbuf
variable:
int loading = 0; void load_file(char *newfile, int ipos) { loading = 1; int insert = (ipos != -1); changed = insert; if (!insert) strcpy(filename, ""); int r; if (!insert) r = textbuf->loadfile(newfile); else r = textbuf->insertfile(newfile, ipos); if (r) fl_alert("Error reading from file \'%s\':\n%s.", newfile, strerror(errno)); else if (!insert) strcpy(filename, newfile); loading = 0; textbuf->call_modify_callbacks(); }
When loading the file we use the Fl_Text_Buffer::loadfile() method to "replace" the text in the buffer, or the Fl_Text_Buffer::insertfile() method to insert text in the buffer from the named file.
void save_file(char *newfile) { if (textbuf->savefile(newfile)) fl_alert("Error writing to file \'%s\':\n%s.", newfile, strerror(errno)); else strcpy(filename, newfile); changed = 0; textbuf->call_modify_callbacks(); }
changed
variable and updates the window label accordingly: void set_title(Fl_Window* w) { if (filename[0] == '\0') strcpy(title, "Untitled"); else { char *slash; slash = strrchr(filename, '/'); #ifdef WIN32 if (slash == NULL) slash = strrchr(filename, '\\'); #endif if (slash != NULL) strcpy(title, slash + 1); else strcpy(title, filename); } if (changed) strcat(title, " (modified)"); w->label(title); }
main()
function. The main()
function creates a new text buffer, creates a new view (window) for the text, shows the window, loads the file on the command-line (if any), and then enters the FLTK event loop:
int main(int argc, char **argv) { textbuf = new Fl_Text_Buffer; Fl_Window* window = new_view(); window->show(1, argv); if (argc > 1) load_file(argv[1], -1); return Fl::run(); }
test/editor.cxx
source file. Both the Makefile and Visual C++ workspace include the necessary rules to build the editor. You can also compile it using a standard compiler with:
CC -o editor editor.cxx -lfltk -lXext -lX11 -lm
or by using the fltk-config
script with:
fltk-config --compile editor.cxx
As noted in Compiling Programs with Standard Compilers, you may need to include compiler and linker options to tell them where to find the FLTK library. Also, the CC
command may also be called gcc
or c++
on your system.
Congratulations, you've just built your own text editor!
Figure 4-2: The completed editor window
Styles are defined using the Fl_Text_Display::Style_Table_Entry structure defined in <FL/Fl_Text_Display.H>
:
The color
member sets the color for the text, the font
member sets the FLTK font index to use, and the size
member sets the pixel size of the text. The attr
member is currently not used.
For our text editor we'll define 7 styles for plain code, comments, keywords, and preprocessor directives:
Fl_Text_Display::Style_Table_Entry styletable[] = { // Style table { FL_BLACK, FL_COURIER, FL_NORMAL_SIZE }, // A - Plain { FL_DARK_GREEN, FL_COURIER_ITALIC, FL_NORMAL_SIZE }, // B - Line comments { FL_DARK_GREEN, FL_COURIER_ITALIC, FL_NORMAL_SIZE }, // C - Block comments { FL_BLUE, FL_COURIER, FL_NORMAL_SIZE }, // D - Strings { FL_DARK_RED, FL_COURIER, FL_NORMAL_SIZE }, // E - Directives { FL_DARK_RED, FL_COURIER_BOLD, FL_NORMAL_SIZE }, // F - Types { FL_BLUE, FL_COURIER_BOLD, FL_NORMAL_SIZE } // G - Keywords };
You'll notice that the comments show a letter next to each style - each style in the style buffer is referenced using a character starting with the letter 'A'.
You call the highlight_data()
method to associate the style data and buffer with the text editor widget:
Fl_Text_Buffer *stylebuf; w->editor->highlight_data(stylebuf, styletable, sizeof(styletable) / sizeof(styletable[0]), 'A', style_unfinished_cb, 0);
Finally, you need to add a callback to the main text buffer so that changes to the text buffer are mirrored in the style buffer:
textbuf->add_modify_callback(style_update, w->editor);
The style_update()
function, like the change_cb()
function described earlier, is called whenever text is added or removed from the text buffer. It mirrors the changes in the style buffer and then updates the style data as necessary:
// // 'style_update()' - Update the style buffer... // void style_update(int pos, // I - Position of update int nInserted, // I - Number of inserted chars int nDeleted, // I - Number of deleted chars int nRestyled, // I - Number of restyled chars const char *deletedText, // I - Text that was deleted void *cbArg) { // I - Callback data int start, // Start of text end; // End of text char last, // Last style on line *style, // Style data *text; // Text data // If this is just a selection change, just unselect the style buffer... if (nInserted == 0 && nDeleted == 0) { stylebuf->unselect(); return; } // Track changes in the text buffer... if (nInserted > 0) { // Insert characters into the style buffer... style = new char[nInserted + 1]; memset(style, 'A', nInserted); style[nInserted] = '\0'; stylebuf->replace(pos, pos + nDeleted, style); delete[] style; } else { // Just delete characters in the style buffer... stylebuf->remove(pos, pos + nDeleted); } // Select the area that was just updated to avoid unnecessary // callbacks... stylebuf->select(pos, pos + nInserted - nDeleted); // Re-parse the changed region; we do this by parsing from the // beginning of the line of the changed region to the end of // the line of the changed region... Then we check the last // style character and keep updating if we have a multi-line // comment character... start = textbuf->line_start(pos); end = textbuf->line_end(pos + nInserted - nDeleted); text = textbuf->text_range(start, end); style = stylebuf->text_range(start, end); last = style[end - start - 1]; style_parse(text, style, end - start); stylebuf->replace(start, end, style); ((Fl_Text_Editor *)cbArg)->redisplay_range(start, end); if (last != style[end - start - 1]) { // The last character on the line changed styles, so reparse the // remainder of the buffer... free(text); free(style); end = textbuf->length(); text = textbuf->text_range(start, end); style = stylebuf->text_range(start, end); style_parse(text, style, end - start); stylebuf->replace(start, end, style); ((Fl_Text_Editor *)cbArg)->redisplay_range(start, end); } free(text); free(style); }
The style_parse()
function scans a copy of the text in the buffer and generates the necessary style characters for display. It assumes that parsing begins at the start of a line:
// // 'style_parse()' - Parse text and produce style data. // void style_parse(const char *text, char *style, int length) { char current; int col; int last; char buf[255], *bufptr; const char *temp; for (current = *style, col = 0, last = 0; length > 0; length --, text ++) { if (current == 'A') { // Check for directives, comments, strings, and keywords... if (col == 0 && *text == '#') { // Set style to directive current = 'E'; } else if (strncmp(text, "//", 2) == 0) { current = 'B'; } else if (strncmp(text, "/*", 2) == 0) { current = 'C'; } else if (strncmp(text, "\\\"", 2) == 0) { // Quoted quote... *style++ = current; *style++ = current; text ++; length --; col += 2; continue; } else if (*text == '\"') { current = 'D'; } else if (!last && islower(*text)) { // Might be a keyword... for (temp = text, bufptr = buf; islower(*temp) && bufptr < (buf + sizeof(buf) - 1); *bufptr++ = *temp++); if (!islower(*temp)) { *bufptr = '\0'; bufptr = buf; if (bsearch(&bufptr, code_types, sizeof(code_types) / sizeof(code_types[0]), sizeof(code_types[0]), compare_keywords)) { while (text < temp) { *style++ = 'F'; text ++; length --; col ++; } text --; length ++; last = 1; continue; } else if (bsearch(&bufptr, code_keywords, sizeof(code_keywords) / sizeof(code_keywords[0]), sizeof(code_keywords[0]), compare_keywords)) { while (text < temp) { *style++ = 'G'; text ++; length --; col ++; } text --; length ++; last = 1; continue; } } } } else if (current == 'C' && strncmp(text, "*/", 2) == 0) { // Close a C comment... *style++ = current; *style++ = current; text ++; length --; current = 'A'; col += 2; continue; } else if (current == 'D') { // Continuing in string... if (strncmp(text, "\\\"", 2) == 0) { // Quoted end quote... *style++ = current; *style++ = current; text ++; length --; col += 2; continue; } else if (*text == '\"') { // End quote... *style++ = current; col ++; current = 'A'; continue; } } // Copy style info... if (current == 'A' && (*text == '{' || *text == '}')) *style++ = 'G'; else *style++ = current; col ++; last = isalnum(*text) || *text == '.'; if (*text == '\n') { // Reset column and possibly reset the style col = 0; if (current == 'B' || current == 'E') current = 'A'; } } }
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